Take the following CSS:
#something{margin:10px;padding:5px}
In NetBeans 6.8, if I highlight "margin:10px;" and hit shift+ctrl+c, the above line would become:
#something{/*margin:10px;*/padding:5px}
This is the correct behavior. Instead, now this happens:
/*#something{margin:10px;padding:5px}*/
I only had "margin:10px;" selected, but it commented out the entire line.
Product Version = NetBeans IDE 7.0 Beta 2 (Build 201102140001)
Operating System = Windows XP version 5.1 running on x86
Java; VM; Vendor = 1.6.0_22
Runtime = Java HotSpot(TM) Client VM 17.1-b03

I understand the request, but currently we do not have an action, which comments out the exactly selected portion of text. Comment* actions toggle comment on the rows at least partially spanned by the selection.
Changing to RFE - valid request, but was not intended to implement by CSL originally :)